During the last six years we have used and developed new techniques for studying the normal masticatory behavior (interrelationships of teeth and physiology, order of contraction and forces generated by jaw muscles) in a series of primitive mammals and primates. The various feeding patterns in the forms studied are simple modifications of a basic pattern and rhythmic jaw activity appears to be determined by a central generator which can be modified by sensory input from the periphery. Preliminary results appear to show that primitive mammals are less reliant on reflex modification and more reliant on a genetically determined rhythm generator. The purpose of this grant is twofold: 1) To substantiate our conclusions on normal masticatory behavior by using a broader spectrum of mammals and more refined techniques. 2) To investigate the neurophysiological control mechanisms governing masticatory behavior. The techniques required for these investigations can not be directly applied to man, but our conclusion that the basic pattern of jaw movement is independent of the morphological differences between the oral structures of the forms studied suggests that the results obtained will be applicable to man and provide an analogue for the experimental investigation of functional disturbances in man.